[apple/xnu.git] / osfmk / kern / lock.h

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * Copyright (C) 1998 Apple Computer
 * All Rights Reserved
 */
/*
 * @OSF_COPYRIGHT@
 */
/* 
 * Mach Operating System
 * Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
 * All Rights Reserved.
 * 
 * Permission to use, copy, modify and distribute this software and its
 * documentation is hereby granted, provided that both the copyright
 * notice and this permission notice appear in all copies of the
 * software, derivative works or modified versions, and any portions
 * thereof, and that both notices appear in supporting documentation.
 * 
 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
 * 
 * Carnegie Mellon requests users of this software to return to
 * 
 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
 *  School of Computer Science
 *  Carnegie Mellon University
 *  Pittsburgh PA 15213-3890
 * 
 * any improvements or extensions that they make and grant Carnegie Mellon
 * the rights to redistribute these changes.
 */
/*
 *	File:	kern/lock.h
 *	Author:	Avadis Tevanian, Jr., Michael Wayne Young
 *	Date:	1985
 *
 *	Higher Level Locking primitives definitions
 */

#ifndef	_KERN_LOCK_H_
#define	_KERN_LOCK_H_

/*
 * Configuration variables:
 *
 *
 *	MACH_LDEBUG:    record pc and thread of callers, turn on
 *			all lock debugging.
 *
 *
 *	ETAP:		The Event Trace Analysis Package (ETAP) monitors
 *			and records micro-kernel lock behavior and general
 *			kernel events.  ETAP supports two levels of
 *			tracing for locks:
 *				- cumulative (ETAP_LOCK_ACCUMULATE)
 *				- monitored  (ETAP_LOCK_MONITOR)
 *
 *			Note: If either level of tracing is configured then
 *			      ETAP_LOCK_TRACE is automatically defined to 
 *			      equal one.
 *
 * 		        Several macros are added throughout the lock code to
 *                      allow for convenient configuration.
 */

#include <kern/simple_lock.h>
#include <machine/lock.h>
#include <mach/etap_events.h>
#include <mach/etap.h>

/*
 *	The Mach lock package exports the following high-level
 *      lock abstractions:
 *
 *	Lock Type  Properties
 *	mutex	   blocking mutual exclusion lock, intended for
 *		   SMP synchronization (vanishes on a uniprocessor);
 *		   supports debugging, statistics, and pre-emption
 *	lock	   blocking synchronization permitting multiple
 *		   simultaneous readers or a single writer; supports
 *		   debugging and statistics but not pre-emption
 *
 *	In general, mutex locks are preferred over all others, as the
 *	mutex supports pre-emption and relinquishes the processor
 *	upon contention.
 *
 */

/*
 *	A simple mutex lock.
 *	Do not change the order of the fields in this structure without
 *	changing the machine-dependent assembler routines which depend
 *	on them.
 */
#ifdef MACH_KERNEL_PRIVATE
#include <mach_ldebug.h>
#include <kern/etap_options.h>
#include <kern/etap_pool.h>

typedef struct {
	hw_lock_data_t	interlock;
	hw_lock_data_t	locked;
	short		waiters;
#if	MACH_LDEBUG
	int		type;
#define	MUTEX_TAG	0x4d4d
	vm_offset_t	pc;
	vm_offset_t	thread;
#endif	/* MACH_LDEBUG */
#if     ETAP_LOCK_TRACE
	union {		/* Must be overlaid on the event_tablep */
	    struct event_table_chain event_table_chain;
	    struct {
		event_table_t   event_tablep;     /* ptr to event table entry */
		etap_time_t	start_hold_time;  /* Time of last acquistion */
	    } s;
	} u;
#endif 	/* ETAP_LOCK_TRACE */
#if     ETAP_LOCK_ACCUMULATE
        cbuff_entry_t  	cbuff_entry;	  /* cumulative buffer entry          */
#endif 	/* ETAP_LOCK_ACCUMULATE */
#if	ETAP_LOCK_MONITOR
        vm_offset_t	start_pc;	  /* pc where lock operation began    */
        vm_offset_t	end_pc;		  /* pc where lock operation ended    */
#endif 	/* ETAP_LOCK_MONITOR */
} mutex_t;

#define	decl_mutex_data(class,name)	class mutex_t name;
#define mutex_addr(m)			(&(m))

#if	MACH_LDEBUG
#define mutex_held(m) (hw_lock_held(&((m)->locked)) && \
		       ((m)->thread == (int)current_thread()))
#else	/* MACH_LDEBUG */
#define mutex_held(m) hw_lock_held(&((m)->locked))
#endif	/* MACH_LDEBUG */

#else /* MACH_KERNEL_PRIVATE */

typedef struct __mutex__ mutex_t;
extern boolean_t mutex_held(mutex_t*);

#endif /* !MACH_KERNEL_PRIVATE */

extern mutex_t *mutex_alloc		(etap_event_t);
extern void	mutex_free		(mutex_t*);

extern void	mutex_init		(mutex_t*, etap_event_t);
extern void	_mutex_lock		(mutex_t*);
extern void	mutex_unlock		(mutex_t*);
extern boolean_t  _mutex_try		(mutex_t*);

extern void	mutex_lock_wait		(mutex_t*);
extern void	mutex_unlock_wakeup	(mutex_t*);
extern void	mutex_pause		(void);
extern void	interlock_unlock	(hw_lock_t);

/*
 *	The general lock structure.  Provides for multiple readers,
 *	upgrading from read to write, and sleeping until the lock
 *	can be gained.
 *
 *	On some architectures, assembly language code in the 'inline'
 *	program fiddles the lock structures.  It must be changed in
 *	concert with the structure layout.
 *
 *	Only the "interlock" field is used for hardware exclusion;
 *	other fields are modified with normal instructions after
 *	acquiring the interlock bit.
 */
#ifdef MACH_KERNEL_PRIVATE
typedef struct {
	decl_simple_lock_data(,interlock) /* "hardware" interlock field */
	volatile unsigned int
		read_count:16,	/* No. of accepted readers */
		want_upgrade:1,	/* Read-to-write upgrade waiting */
		want_write:1,	/* Writer is waiting, or
				   locked for write */
		waiting:1,	/* Someone is sleeping on lock */
		can_sleep:1;	/* Can attempts to lock go to sleep? */
#if     ETAP_LOCK_TRACE
	union {		/* Must be overlaid on the event_tablep */
	    struct event_table_chain event_table_chain;
	    struct {
		event_table_t event_tablep;	/* ptr to event table entry */
		start_data_node_t start_list;	/* linked list of start times
						   and pcs */
	    } s;
	} u;
#endif 	/* ETAP_LOCK_TRACE */
#if     ETAP_LOCK_ACCUMULATE
       	cbuff_entry_t	cbuff_write;	/* write cumulative buffer entry      */
	cbuff_entry_t	cbuff_read;	/* read  cumulative buffer entry      */
#endif 	/* ETAP_LOCK_ACCUMULATE */
} lock_t;

/* Sleep locks must work even if no multiprocessing */

/*
 * Complex lock operations
 */

#if ETAP
/*
 *	Locks have a pointer into an event_table entry that names the
 *	corresponding lock event and controls whether it is being traced.
 *	Initially this pointer is into a read-only table event_table_init[].
 *	Once dynamic allocation becomes possible a modifiable copy of the table
 *	is allocated and pointers are set to within this copy.  The pointers
 *	that were already in place at that point need to be switched to point
 *	into the copy.  To do this we overlay the event_table_chain structure
 *	onto sufficiently-big elements of the various lock structures so we
 *	can sweep down this list switching the pointers.  The assumption is
 *	that we will not want to enable tracing before this is done (which is
 *	after all during kernel bootstrap, before any user tasks are launched).
 *
 *	This is admittedly rather ugly but so were the alternatives:
 *	- record the event_table pointers in a statically-allocated array
 *	  (dynamic allocation not yet being available) -- but there were
 *	  over 8000 of them;
 *	- add a new link field to each lock structure;
 *	- change pointers to array indices -- this adds quite a bit of
 *	  arithmetic to every lock operation that might be traced.
 */
#define lock_event_table(lockp)		((lockp)->u.s.event_tablep)
#define lock_start_hold_time(lockp)	((lockp)->u.s.start_hold_time)
#endif	/* ETAP_LOCK_TRACE */

extern void	lock_init		(lock_t*,
					 boolean_t,
					 etap_event_t,
					 etap_event_t);

#else /* MACH_KERNEL_PRIVATE */

typedef struct __lock__ lock_t;
extern lock_t *lock_alloc(boolean_t, etap_event_t, etap_event_t);
void lock_free(lock_t *);

#endif /* !MACH_KERNEL_PRIVATE */

extern void	lock_write		(lock_t*);
extern void	lock_read		(lock_t*);
extern void	lock_done		(lock_t*);
extern void	lock_write_to_read	(lock_t*);

#define	lock_read_done(l)		lock_done(l)
#define	lock_write_done(l)		lock_done(l)

extern boolean_t lock_read_to_write	(lock_t*);  /* vm_map is only user */
extern unsigned int LockTimeOut;				/* Standard lock timeout value */

#endif	/* _KERN_LOCK_H_ */
Commit	Line	Data
1c79356b A	1	/*
	2	* Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
	6	* The contents of this file constitute Original Code as defined in and
	7	* are subject to the Apple Public Source License Version 1.1 (the
	8	* "License"). You may not use this file except in compliance with the
	9	* License. Please obtain a copy of the License at
	10	* http://www.apple.com/publicsource and read it before using this file.
	11	*
	12	* This Original Code and all software distributed under the License are
	13	* distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
	14	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
	15	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
	16	* FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
	17	* License for the specific language governing rights and limitations
	18	* under the License.
	19	*
	20	* @APPLE_LICENSE_HEADER_END@
	21	*/
	22	/*
	23	* Copyright (C) 1998 Apple Computer
	24	* All Rights Reserved
	25	*/
	26	/*
	27	* @OSF_COPYRIGHT@
	28	*/
	29	/*
	30	* Mach Operating System
	31	* Copyright (c) 1991,1990,1989,1988,1987 Carnegie Mellon University
	32	* All Rights Reserved.
	33	*
	34	* Permission to use, copy, modify and distribute this software and its
	35	* documentation is hereby granted, provided that both the copyright
	36	* notice and this permission notice appear in all copies of the
	37	* software, derivative works or modified versions, and any portions
	38	* thereof, and that both notices appear in supporting documentation.
	39	*
	40	* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
	41	* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
	42	* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
	43	*
	44	* Carnegie Mellon requests users of this software to return to
	45	*
	46	* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
	47	* School of Computer Science
	48	* Carnegie Mellon University
	49	* Pittsburgh PA 15213-3890
	50	*
	51	* any improvements or extensions that they make and grant Carnegie Mellon
	52	* the rights to redistribute these changes.
	53	*/
	54	/*
	55	* File: kern/lock.h
	56	* Author: Avadis Tevanian, Jr., Michael Wayne Young
	57	* Date: 1985
	58	*
	59	* Higher Level Locking primitives definitions
	60	*/
	61
	62	#ifndef _KERN_LOCK_H_
	63	#define _KERN_LOCK_H_
	64
65	/*
66	* Configuration variables:
67	*
68	*
69	* MACH_LDEBUG: record pc and thread of callers, turn on
70	* all lock debugging.
71	*
72	*
73	* ETAP: The Event Trace Analysis Package (ETAP) monitors
74	* and records micro-kernel lock behavior and general
75	* kernel events. ETAP supports two levels of
76	* tracing for locks:
77	* - cumulative (ETAP_LOCK_ACCUMULATE)
78	* - monitored (ETAP_LOCK_MONITOR)
79	*
80	* Note: If either level of tracing is configured then
81	* ETAP_LOCK_TRACE is automatically defined to
82	* equal one.
83	*
84	* Several macros are added throughout the lock code to
85	* allow for convenient configuration.
86	*/
87
88	#include <kern/simple_lock.h>
89	#include <machine/lock.h>
90	#include <mach/etap_events.h>
91	#include <mach/etap.h>
92
93	/*
94	* The Mach lock package exports the following high-level
95	* lock abstractions:
96	*
97	* Lock Type Properties
98	* mutex blocking mutual exclusion lock, intended for
99	* SMP synchronization (vanishes on a uniprocessor);
100	* supports debugging, statistics, and pre-emption
101	* lock blocking synchronization permitting multiple
102	* simultaneous readers or a single writer; supports
103	* debugging and statistics but not pre-emption
104	*
105	* In general, mutex locks are preferred over all others, as the
106	* mutex supports pre-emption and relinquishes the processor
107	* upon contention.
108	*
109	*/
110
111	/*
112	* A simple mutex lock.
113	* Do not change the order of the fields in this structure without
114	* changing the machine-dependent assembler routines which depend
115	* on them.
116	*/
117	#ifdef MACH_KERNEL_PRIVATE
118	#include <mach_ldebug.h>
119	#include <kern/etap_options.h>
120	#include <kern/etap_pool.h>
121
122	typedef struct {
123	hw_lock_data_t interlock;
124	hw_lock_data_t locked;
125	short waiters;
126	#if MACH_LDEBUG
127	int type;
128	#define MUTEX_TAG 0x4d4d
129	vm_offset_t pc;
130	vm_offset_t thread;
131	#endif /* MACH_LDEBUG */
132	#if ETAP_LOCK_TRACE
133	union { /* Must be overlaid on the event_tablep */
134	struct event_table_chain event_table_chain;
135	struct {
136	event_table_t event_tablep; /* ptr to event table entry */
137	etap_time_t start_hold_time; /* Time of last acquistion */
138	} s;
139	} u;
140	#endif /* ETAP_LOCK_TRACE */
141	#if ETAP_LOCK_ACCUMULATE
142	cbuff_entry_t cbuff_entry; /* cumulative buffer entry */
143	#endif /* ETAP_LOCK_ACCUMULATE */
144	#if ETAP_LOCK_MONITOR
145	vm_offset_t start_pc; /* pc where lock operation began */
146	vm_offset_t end_pc; /* pc where lock operation ended */
147	#endif /* ETAP_LOCK_MONITOR */
148	} mutex_t;
149
150	#define decl_mutex_data(class,name) class mutex_t name;
151	#define mutex_addr(m) (&(m))
152
153	#if MACH_LDEBUG
154	#define mutex_held(m) (hw_lock_held(&((m)->locked)) && \
155	((m)->thread == (int)current_thread()))
156	#else /* MACH_LDEBUG */
157	#define mutex_held(m) hw_lock_held(&((m)->locked))
158	#endif /* MACH_LDEBUG */
159
160	#else /* MACH_KERNEL_PRIVATE */
161
162	typedef struct __mutex__ mutex_t;
163	extern boolean_t mutex_held(mutex_t*);
164
165	#endif /* !MACH_KERNEL_PRIVATE */
166
167	extern mutex_t *mutex_alloc (etap_event_t);
168	extern void mutex_free (mutex_t*);
169
170	extern void mutex_init (mutex_t*, etap_event_t);
171	extern void _mutex_lock (mutex_t*);
172	extern void mutex_unlock (mutex_t*);
173	extern boolean_t _mutex_try (mutex_t*);
174
175	extern void mutex_lock_wait (mutex_t*);
176	extern void mutex_unlock_wakeup (mutex_t*);
177	extern void mutex_pause (void);
178	extern void interlock_unlock (hw_lock_t);
179
180	/*
181	* The general lock structure. Provides for multiple readers,
182	* upgrading from read to write, and sleeping until the lock
183	* can be gained.
184	*
185	* On some architectures, assembly language code in the 'inline'
186	* program fiddles the lock structures. It must be changed in
187	* concert with the structure layout.
188	*
189	* Only the "interlock" field is used for hardware exclusion;
190	* other fields are modified with normal instructions after
191	* acquiring the interlock bit.
192	*/
193	#ifdef MACH_KERNEL_PRIVATE
194	typedef struct {
195	decl_simple_lock_data(,interlock) /* "hardware" interlock field */
196	volatile unsigned int
197	read_count:16, /* No. of accepted readers */
198	want_upgrade:1, /* Read-to-write upgrade waiting */
199	want_write:1, /* Writer is waiting, or
200	locked for write */
201	waiting:1, /* Someone is sleeping on lock */
202	can_sleep:1; /* Can attempts to lock go to sleep? */
203	#if ETAP_LOCK_TRACE
204	union { /* Must be overlaid on the event_tablep */
205	struct event_table_chain event_table_chain;
206	struct {
207	event_table_t event_tablep; /* ptr to event table entry */
208	start_data_node_t start_list; /* linked list of start times
209	and pcs */
210	} s;
211	} u;
212	#endif /* ETAP_LOCK_TRACE */
213	#if ETAP_LOCK_ACCUMULATE
214	cbuff_entry_t cbuff_write; /* write cumulative buffer entry */
215	cbuff_entry_t cbuff_read; /* read cumulative buffer entry */
216	#endif /* ETAP_LOCK_ACCUMULATE */
217	} lock_t;
218
219	/* Sleep locks must work even if no multiprocessing */
220
221	/*
222	* Complex lock operations
223	*/
224
225	#if ETAP
226	/*
227	* Locks have a pointer into an event_table entry that names the
228	* corresponding lock event and controls whether it is being traced.
229	* Initially this pointer is into a read-only table event_table_init[].
230	* Once dynamic allocation becomes possible a modifiable copy of the table
231	* is allocated and pointers are set to within this copy. The pointers
232	* that were already in place at that point need to be switched to point
233	* into the copy. To do this we overlay the event_table_chain structure
234	* onto sufficiently-big elements of the various lock structures so we
235	* can sweep down this list switching the pointers. The assumption is
236	* that we will not want to enable tracing before this is done (which is
237	* after all during kernel bootstrap, before any user tasks are launched).
238	*
239	* This is admittedly rather ugly but so were the alternatives:
240	* - record the event_table pointers in a statically-allocated array
241	* (dynamic allocation not yet being available) -- but there were
242	* over 8000 of them;
243	* - add a new link field to each lock structure;
244	* - change pointers to array indices -- this adds quite a bit of
245	* arithmetic to every lock operation that might be traced.
246	*/
247	#define lock_event_table(lockp) ((lockp)->u.s.event_tablep)
248	#define lock_start_hold_time(lockp) ((lockp)->u.s.start_hold_time)
249	#endif /* ETAP_LOCK_TRACE */
250
251	extern void lock_init (lock_t*,
252	boolean_t,
253	etap_event_t,
254	etap_event_t);
255
256	#else /* MACH_KERNEL_PRIVATE */
257
258	typedef struct __lock__ lock_t;
259	extern lock_t *lock_alloc(boolean_t, etap_event_t, etap_event_t);
260	void lock_free(lock_t *);
261
262	#endif /* !MACH_KERNEL_PRIVATE */
263
264	extern void lock_write (lock_t*);
265	extern void lock_read (lock_t*);
266	extern void lock_done (lock_t*);
267	extern void lock_write_to_read (lock_t*);
268
269	#define lock_read_done(l) lock_done(l)
270	#define lock_write_done(l) lock_done(l)
271
272	extern boolean_t lock_read_to_write (lock_t); / vm_map is only user */
273	extern unsigned int LockTimeOut; /* Standard lock timeout value */
274
275	#endif /* _KERN_LOCK_H_ */